The acoustic excitation of energetic materials has been demonstrated to be useful in detection and defeat applications, but its efficacy is hindered by the inability to transmit a high percentage of incident acoustic energy across the air/energetic material interface. While large acoustical impedance differences usually prevent energy transmission from air into a solid, inhomogeneous incident waves have been found to transmit a significant percentage of their energy into the target material. Thus, inhomogeneous waves, whose amplitudes decay spatially in a direction different from the propagation direction, are an optimal choice for this application; however, it is difficult to create such a waveform by using a simple source. The objective of the present work is to demonstrate that by tuning the strengths and phases of sound sources in a linear array, an interference pattern can be generated such that an inhomogeneous wave forms on a surface of interest. Furthermore, it is demonstrated that by adjusting the level of inhomogeneity of the wave and its incidence angle, one can target the parameters associated with optimal sound transmission, and that these waves can be generated even in the presence of small errors in the powers and phases of the sources.
Sound transmission, Solids, Inhomogeneous plane wave
Acoustics and Noise Control
Date of this Version